1. Field of the Invention
The invention relates to a mechanism for rinsing the ink channels and nozzles of a print head in ink printer devices by use of a hose pump arranged between an ink reservoir and an ink distributing system of the print head.
2. Description of the Prior Art
It is most essential for the reliable operation of a print head of an ink printer operating according to what is referred to as the under-pressure method that the ink channels always be completely filled with ink. Contaminations and air or gas bubbles in the channel and/or in the nozzle region lead to considerable disturbances in the function and are not infrequently the reason for the complete outage of the print head. This malfunction can be eliminated by means of a rinsing event wherein ink is pressed through the channel and nozzle region by means of a chronologically limited over-pressure.
A rinsing mechanism is described in German Patent No. 26 10 518 wherein an over-pressure is manually generated for a brief time by actuating a plunger in the print head. When the static under-pressure is restored, the desired, negative ink meniscus is again formed in every nozzle opening. The quantity of ink used by the rinsing procedure, however, can fluctuate within wide limits and can lead to considerable losses and waste problems.
A mechanical device for eliminating dirt particles and air bubbles from the print head of an ink printer means is described in German OS No. 29 14 986 wherein an elastic ink conveying hose includes a portion fashioned as a hose pump which can be brought into contact with a pinch member for conveying ink in the direction of the print head. A relatively long connecting hose leads from the hose pump to the print head in order not to impede its movement. In addition to the risk of mechanical damage to the conveying hose, additional measures against twisting and buckling are to be provided.